Generally, in a horizontal device having the hetero-junction structure, there is a trade-off relationship between a breakdown voltage and an on-resistance. If one is improved, the other is likely to be sacrificed. In order to further improve characteristics of the semiconductor element, the trade-off relationship between the breakdown voltage and the on-resistance needs to be improved.
Patent literature 1 proposes an element structure capable of improving the trade-off relationship between the breakdown voltage and the on-resistance. Specifically, a voltage resistance, that is, the breakdown voltage is improved by a structure in which a semiconductor element such as a diode or a transistor includes the same quantity of 2-dimensional electric gas (hereinafter, 2DEG) and 2-dimensional hole gas (hereinafter, 2DHG).